Currently the spinning of yarn is achieved by rotating ‘cones’ at a high speed. Cones, which are set on spindles, are rotated by an electric motor that drives all the spindles on a frame. A frame can have up to 400 or more spindles on it. Drive shafts and rubber based belts are employed to spin the spindles. As a consequence of this spinning action, a passive ‘ring’ is made to rotate on its holding assembly, that actually puts the twist on the yarn. The twist is counted as ‘TPI’ or ‘twists per inch’. Twist count on the yarn is achieved by the spinning action of the yarn while traveling between the drafting rollers and spinning ring, after which it is wound on the cone. At the start of this cycle, the spinning ring is at the lowest end of the cone, and as the cone begins to fill up, it travels up until it reaches the top of the cone where the cycle ends. This upward motion of the spinning ring is necessary in order to collect the spun yarn on the cone.
The main compromises in the system are: (a) All the spindles must rotate when the motor is turned on. (b) Distance between the spinning ring and the drafting roller can not be fixed due to the up and down reciprocation of the ring, which is absolutely necessary for the take-up of the yarn. This means that the most optimum spinning geometry cannot be achieved. (c) Since all spindles must be rotated and other tasks also performed, the main motor has to be of a high wattage. (d) In case of yarn breakage at one of the spindles, either the entire spinning frame must be stopped or that particular spindle may be abandoned or the yarn spliced on a running machine. (e) Due to these mechanical dictations at the start of the cycle the ring is at its farthest distance from the drafting assembly. All these design compromises affect the quality of the spun yarn.
U.S. Pat. No. 5,396,757 overcame certain disadvantages of traditional spinning mechanism by using a single motor to drive each spindle separately. The invention also discloses a method to control the jumping of the spindles. If there is yarn breakage at a given spindle, by this invention it is not necessary to stop the whole spindle assembly. Because each motor controls a single spindle, respective motor can be stopped and the damage can be fixed without negotiating the productivity.
U.S. Pat. No. 6,205,759 B1 also discloses individual spindle drive type textile machines where each motor drives a single spindle. Spindle units are arranged in parallel arrays. If one spindle unit gives trouble, there is no requirement to stop the entire spindle unit. This invention also discloses the use of a circuit box, which controls the speed of each spindle unit.
One objective of the present device is to reduce yarn breakage. In presently available systems, the spindle is fixed at a specific position and a spindle ring having a guide moves up and down along the spindle winding the yarn. At the start of the spinning process, when there is no yarn on the bobbin, the spindle ring lies at the bottom of the spindle. Therefore, initially, the distance between the ring and the rollers is large (because the spindle ring lies at the bottom of the spindle) and also the ring is not held firmly since there is no yarn on the bobbin. This increases the tension of the yarn, resulting in breakage of the yarn. Traditionally during the initial spinning process, the spindles are rotated slowly to avoid the breakage of the yarn. This slow initial spinning process reduces the productivity of the yarn wound onto the spool. Prior art has no efficient method for controlling the yarn breakage and also prior art has no efficient method for determining the number of twists and turns needed for optimum winding.
In these respects, the spindle spinning mechanism according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides a machine primarily developed for the purpose of yarn spinning and pre-determination of number of twists and turns which is controlled by a computer.